The implications of immunogenicity for protein-based multiple sclerosis therapies

Specific sequence mutations in a long-lasting rhIFN-α2b version reduce in vitro and in vivo immunogenicity and increase in vitro protein stability

For decades, recombinant human interferon alpha (rhIFN-α2b) has been used to treat emerging and chronic viral diseases. However, rhIFN-α2b is immunogenic and has a short in vivo half-life. To solve these limitations, two long-lasting hyperglycosylated proteins with reduced immunogenicity were developed and designated as 4N-IFN(VAR1) and 4N-IFN(VAR3). Here, we continue to study the relevant characteristics of these therapeutic candidates. Thus, we demonstrated that both de-immunized IFN versions elicited significantly lower neutralizing antibody responses than the original molecule in HLA-DR1 transgenic mice, confirming our previous in vitro protein immunogenicity data. Also, we found that these biobetters exhibited remarkable stability when exposed to different physical factors that the protein product may encounter during its production process and storage, such as low pH, thermal stress, and repeated freezing/thawing cycles. Taking into consideration our previous and present results, 4N-IFN(VAR1) and 4N-IFN-4N(VAR3) appear to be valuable candidates for the treatment of human viral diseases.

Antidrug Antibodies Against Biological Treatments for Multiple Sclerosis

The development of antidrug antibodies (ADAs) is a major problem in several recombinant protein therapies used in the treatment of multiple sclerosis (MS). The etiology of ADAs is multifaceted. The predisposition for a breakdown of immune tolerance is probably genetically determined, and many factors may contribute to the immunogenicity, including structural properties, formation of aggregates, and presence of contaminants and impurities from the industrial manufacturing process. ADAs may have a neutralizing capacity and can reduce or abrogate the bioactivity and therapeutic efficacy of the drug and cause safety issues. Interferon (IFN)-β was the first drug approved for the treatment of MS, and-although it is generally recognized that neutralizing antibodies (NAbs) appear and potentially have a negative effect on therapeutic efficacy-the use of routine measurements of NAbs and the interpretation of the presence of NAbs has been debated at length. NAbs appear after 9-18 months of therapy in up to 40% of patients treated with IFNβ, and the frequency and titers of NAbs depend on the IFNβ preparation. Although all pivotal clinical trials of approved IFNβ products in MS exhibited a detrimental effect of NAbs after prolonged therapy, some subsequent studies did not observe clinical effects from NAbs, which led to the claim that NAbs did not matter. However, it is now largely agreed that persistently high titers of NAbs indicate an abrogation of the biological response and, hence, an absence of therapeutic efficacy, and this observation should lead to a change of therapy. Low and medium titers are ambiguous, and treatment decisions should be guided by determination of in vivo messenger RNA myxovirus resistance protein A induction after IFNβ administration and clinical disease activity. During treatment with glatiramer acetate, ADAs occur frequently but do not appear to adversely affect treatment efficacy or result in adverse events. ADAs occur in approximately 5% of patients treated with natalizumab within 6 months of therapy, and persistent NAbs are associated with a lack of efficacy and acute infusion-related reactions and should instigate a change of therapy. When using the anti-CD20 monoclonal antibodies ocrelizumab and ofatumumab in the treatment of MS, it is not necessary to test for NAbs as these occur very infrequently. Alemtuzumab is immunogenic, but routine measurements of ADAs are not recommended as the antibodies in the pivotal 2-year trials at the population level did not influence lymphocyte depletion or repopulation, efficacy, or safety. However, in some individuals, NAbs led to poor lymphocyte depletion.

Preclinical immunogenicity testing using anti-drug antibody analysis of GX-G3, Fc-fused recombinant human granulocyte colony-stimulating factor, in rat and monkey models

Human granulocyte colony-stimulating factor (G-CSF, this study used Fc-fused recombinant G-CSF; GX-G3) is an important glycoprotein that stimulates the proliferation of granulocytes and white blood cells. Thus, G-CSF treatment has been considered as a crucial regimen to accelerate recovery from chemotherapy-induced neutropenia in cancer patients suffering from non-myeloid malignancy or acute myeloid leukemia. Despite the therapeutic advantages of G-CSF treatment, an assessment of its immunogenicity must be performed to determine whether the production of anti-G-CSF antibodies causes immune-related disorders. We optimized and validated analytical tools by adopting validation parameters for immunogenicity assessment. Using these validated tools, we analyzed serum samples from rats and monkeys injected subcutaneously with GX-G3 (1, 3 or 10 mg/kg once a week for 4 weeks followed by a 4-week recovery period) to determine immunogenicity response and toxicokinetic parameters with serum concentration of GX-G3. Several rats and monkeys were determined to be positive for anti-GX-G3 antibodies. Moreover, the immunogenicity response of GX-G3 was lower in monkeys than in rats, which was relevant to show less inhibition of toxicokinetic profiles in monkeys, at least 1 mg/kg administrated group, compared to rats. These results suggested the establishment and validation for analyzing anti-GX-G3 antibodies and measurement of serum levels of GX-G3 and anti-GX-G3 antibodies, which was related with toxicokinetic profiles. Taken together, this study provides immunogenicity assessment which is closely implicated with toxicokinetic study of GX-G3 in 4-week repeated administrated toxicological studies.

Engineering therapeutic antibodies for patient safety: tackling the immunogenicity problem

Established monoclonal antibodies (mAbs) allow treatment of cancers, autoimmune diseases and other severe illnesses. Side effects either arise due to interaction with the target protein and its biology or result from of the patient's immune system reacting to the foreign protein. This immunogenic reaction against therapeutic antibodies is dependent on various factors. The presence of non-human sequences can trigger immune responses as well as chemical and post-translational modifications of the antibody. However, even fully human antibodies can induce immune response through T cell epitopes or aggregates. In this review, we briefly describe, how therapeutic antibodies can interact with the patient's immune system and summarize recent advancements in protein engineering and in silico methods to reduce immunogenicity of therapeutic monoclonal antibodies.

AJM300, a novel oral antagonist of α4-integrin, sustains an increase in circulating lymphocytes: A randomised controlled trial in healthy male subjects

Aims

AJM300 is an oral antagonist of α4‐integrin that reduces inflammation by blocking leucocyte trafficking. This study aimed to investigate safety, tolerability, pharmacokinetics and pharmacodynamics of AJM300 in healthy male subjects.

Methods

A total of 23 subjects were randomised to receive 240 mg (n = 6), 480 mg (n = 5), 960 mg (n = 6) of AJM300 or the corresponding placebo (n = 2 per group). The study drugs were taken orally 3 times daily after each meal on the first day followed by a 4‐day washout period. Thereafter, multiple‐dose administration was conducted for 6 consecutive days. The pharmacokinetic parameters of AJM300 and its active metabolite (HCA2969) were assessed, and total white blood cells and the differential cell count were used to determine the pharmacodynamic effects. Adverse events (AEs) were also monitored.

Results

The plasma AJM300 and HCA2969 concentration–time curves displayed a triphasic pattern on Day 1 (single‐day administration) and Day 10 (last day of multiple dosing), whereas the concentration of HCA2969 was much higher than that of AJM300. A significant but transient increase in lymphocyte count was observed after AJM300 dosing at all dosages tested compared with the placebo. The increase was sustained over a 24‐h period only at the 960‐mg dosage. In particular, a significant increase in the lymphocyte count compared to placebo (mean, 50.58%; 95% confidence intervals, 20.40–80.76) was observed at the first 960‐mg dose on Day 10. Six (26.1%) subjects reported ≥1 AEs, all of which were mild and resolved spontaneously.

Conclusion

The maximal and 24‐h sustained pharmacodynamic effects were demonstrated at the 960‐mg dosage after oral administration of AJM300 3 times daily for 6 days, which was also found to be safe and well tolerated.

The EU regulatory landscape of non-biological complex drugs (NBCDs) follow-on products: Observations and recommendations

"Non-biological complex drugs" (NBCDs), such as liposomal formulations, iron-carbohydrate complexes and glatiramoids, gained increased interest from a regulatory perspective in recent years. Similar to biologics, the quality of NBCD products is highly dependent on a robust and well-controlled manufacturing process. This provides challenges for generic drug developers to replicate NBCD products once market exclusivity of the originator product is expired. However, unlike biologics for which a consistent regulatory framework was established with the biosimilars pathway, NBCDs are not recognised as a distinct category of medicines and hence no formal regulatory pathway for their approval is defined. Currently, a "case-by-case" approach is applied for regulating NBCD follow-on products in the EU. Furthermore, NBCDs can follow a non-centralised authorisation procedure, leaving regulatory approvals to national competent authorities. This can lead to heterogeneity in the regulatory approach and outcomes when assessing NBCD follow-on products throughout the EU, which for some product classes has already resulted in some safety and efficacy implications. Here, we explore the regulatory landscape of NBCDs and their follow on products. This study shows that almost all of the 85 NBCD follow-on products available in the EU in 2018 have been approved via various non-centralised procedures. Although most NBCD follow-on products followed an Article 10(1) procedure, we clearly see a recent increase of the use of the hybrid pathway via Article 10(3). This study shows the heterogeneity in the regulatory approach taken for many NBCD follow on products. To what extent this may have consequences for their safety and efficacy evaluations is unknown and needs to be further investigated. The present study should stimulate the rethinking to design prudent regulatory pathways for NBCD follow-on products.

Immunogenicity of Innovative and Biosimilar Monoclonal Antibodies

The development of hybridoma technology for producing monoclonal antibodies (mAbs) by Kohler and Milstein (1975) counts as one of the major medical breakthroughs, opening up endless possibilities for research, diagnosis and for treatment of a whole variety of diseases. Therapeutic mAbs were introduced three decades ago. The first generation of therapeutic mAbs of murine origin showed high immunogenicity, which limited efficacy and was associated with severe infusion reactions. Subsequently chimeric, humanized, and fully human antibodies were introduced as therapeutics, these mAbs were considerably less immunogenic. Unexpectedly humanized mAbs generally show similar immunogenicity as chimeric antibodies; based on sequence homology chimeric mAbs are sometimes more “human” than humanized mAbs. With the introduction of the regulatory concept of similar biological medicines (biosimilars) a key concern is the similarity in terms of immunogenicity of these biosimilars with their originators. This review focuses briefly on the mechanisms of induction of immunogenicity by biopharmaceuticals, mAbs in particular, in relation to the target of the immune system.

Monoclonal Antibodies: Past, Present and Future

Monoclonal antibodies (mAbs) are immunoglobulins designed to target a specific epitope on an antigen. Immunoglobulins of identical amino-acid sequence were originally produced by hybridomas grown in culture and, subsequently, by recombinant DNA technology using mammalian cell expression systems. The antigen-binding region of the mAb is formed by the variable domains of the heavy and light chains and contains the complementarity-determining region that imparts the high specificity for the target antigen. The pharmacokinetics of mAbs involves target-mediated and non-target-related factors that influence their disposition.Preclinical safety evaluation of mAbs differs substantially from that of small molecular (chemical) entities. Immunogenicity of mAbs has implications for their pharmacokinetics and safety. Early studies of mAbs in humans require careful consideration of the most suitable study population, route/s of administration, starting dose, study design and the potential difference in pharmacokinetics in healthy subjects compared to patients expressing the target antigen.Of the ever-increasing diversity of therapeutic indications for mAbs, we have concentrated on two that have proved dramatically successful. The contribution that mAbs have made to the treatment of inflammatory conditions, in particular arthritides and inflammatory bowel disease, has been nothing short of revolutionary. Their benefit has also been striking in the treatment of solid tumours and, most recently, as immunotherapy for a wide variety of cancers. Finally, we speculate on the future with various new approaches to the development of therapeutic antibodies.

Immunomodulatory effects of a rationally designed peptide mimetic of human IFNβ in EAE model of multiple sclerosis

The efficiency of interferon beta (IFNβ)-based drugs is considerably limited due to their undesirable properties, especially high immunogenicity. In this study, for the first time we investigated the impact of a computationally designed peptide mimetic of IFNβ, called MSPEP27, in the animal model of MS. A peptide library was constructed using the Rosetta program based on the predominant IFNAR1-binding site of IFNβ. Molecular docking studies were carried out using ClusPro and HADDOCK tools. The GROMACS package was subsequently used for molecular dynamics (MD) simulations. Validation of peptide-receptor interaction was carried out using intrinsic fluorescence measurements. To explore in silico findings further, experimental autoimmune encephalomyelitis (EAE) was induced by subcutaneous immunization of myelin oligodendrocyte glycoprotein (MOG35-55). Mice were then separated into distinct groups and intravenously received 10 or 20mgkg^-1 of MSPEP27 or IFNβ. The inflammatory mediators were monitored by immunohistochemistry (IL17, CD11b, CD45), quantitative real-time PCR (MMP2, MMP9, TIMP-1) and enzyme-linked immunosorbent assay (IL1β, TNFα) methods. Among the library of tolerated peptides, MSPEP27, a peptide with favorable physicochemical properties, was chosen for further experiments. This peptide was shown to significantly interact with IFNAR1 in a dose-dependent manner. Like IFNβ, MSPEP27 could efficiently bind to IFNAR1 and form a stable peptide-receptor complex during 30ns MD simulations. In vivo analyses revealed that MSPEP27 could lessen inflammation by modulating the levels of inflammatory mediators. According to our results, MSPEP27 peptide could efficiently bind to IFNAR1 and suppress neuroinflammation in vivo. We conclude that MSPEP27 has protective effects against MOG-induced EAE via reduction of immune dysfunction and inflammation.

Alemtuzumab depletion failure can occur in multiple sclerosis

Alemtuzumab is a lymphocyte-depleting antibody and one of the most effective treatments for relapsing multiple sclerosis. However, it also causes loss of immune-tolerance leading to secondary autoimmunity and marked anti-drug antibody responses. Although these anti-drug responses have been reported to be of no significance, we hypothesized that they will affect the depleting capacity and treatment response in some individuals. This was found following analysis of the regulatory submission of the pivotal phase III trials, which was obtained from the European Medicines Agency. At the population level there was lack of influence of 'ever-positive' alemtuzumab-specific antibody responses on lymphocyte depletion, clinical efficacy and adverse effects during the 2-year trial. This was not surprising as no one before the first infusion, and only 0·6% of people before the second-infusion, had pre-infusion, neutralizing antibodies (NAbs). However, at the individual level, NAbs led to poor lymphocyte depletion. Importantly, it was evident that 31% of people had NAbs and 75% had binding antibodies at the end of treatment-cycle 2, which suggests that problems may occur in people requiring additional alemtuzumab cycles. In addition, we also identified individuals, following 'post-marketing' alemtuzumab use, whose lymphocyte level was never effectively depleted after the first infusion cycle. Hence, although alemtuzumab depletes lymphocytes in most individuals, some people fail to deplete/deplete poorly, probably due to biological-response variation and NAbs, and this may lead to treatment failure. Monitoring depletion following infusion and assessment of the neutralizing response before re-infusion may help inform the decision to retreat or switch therapy to limit treatment failure.

De-immunized and Functional Therapeutic (DeFT) versions of a long lasting recombinant alpha interferon for antiviral therapy

Interferon α (IFN-α) exerts potent antiviral, immunomodulatory, and antiproliferative activity and have proven clinical utility in chronic hepatitis B and C virus infections. However, repeated IFN-α administration induces neutralizing antibodies (NAb) against the therapeutic in a significant number of patients. Associations between IFN-α immunogenicity and loss of efficacy have been described. So as to improve the in vivo biological efficacy of IFN-α, a long lasting hyperglycosylated protein (4N-IFN) derived from IFN-α2b wild type (WT-IFN) was developed. However, in silico analysis performed using established in silico methods revealed that 4N-IFN had more T cell epitopes than WT-IFN. In order to develop a safer and more efficient IFN therapy, we applied the DeFT (De-immunization of Functional Therapeutics) approach to producing functional, de-immunized versions of 4N-IFN. Using the OptiMatrix in silico tool in ISPRI, the 4N-IFN sequence was modified to reduce HLA binding potential of specific T cell epitopes. Following verification of predictions by HLA binding assays, eight modifications were selected and integrated in three variants: 4N-IFN(VAR1), (VAR2) and (VAR3). Two of the three variants (VAR1 and VAR3) retained anti-viral function and demonstrated reduced T-cell immunogenicity in terms of T-cell proliferation and Th1 and Th2 cytokine levels, when compared to controls (commercial NG-IFN (non-glycosylated), PEG-IFN, WT-IFN and 4N-IFN). It was previously demonstrated that N-glycosylation improved IFN-α pharmacokinetic properties. Here, we further reduce immunogenicity as measured in vitro using T cell assays and cytokine profiling by modifying the T cell epitope content of a protein (de-immunizing). Taking into consideration the present results and previously reported immunogenicity data for commercial IFN-α2b variants, 4N-IFN(VAR1) and 4N-IFN-4N(VAR3) appear to be promising candidates for improved IFN-α therapy of HCV and HBV.

The immunogenicity of biosimilar infliximab: can we extrapolate the data across indications?

Biopharmaceuticals or 'biologics' have revolutionized the treatment of many diseases. However, some patients generate an immune response to such drugs, potentially limiting clinical efficacy and safety. Infliximab (Remicade(®)) is a monoclonal antibody used to treat several immune-mediated inflammatory disorders. A biosimilar of infliximab, CT-P13 (Remsima(®), Inflectra(®)), has recently been approved in Europe for all indications in which infliximab is approved. Approval of CT-P13 was based in part on extrapolation of clinical trial data from two indications (rheumatoid arthritis and ankylosing spondylitis) to all other indications, including inflammatory bowel disease. This review discusses the validity of extrapolating immunogenicity data across indications - a process adopted by the EMA as part of their biosimilar approval process - with a focus on CT-P13.

Interferon beta treatment of multiple sclerosis increases serum interleukin-7

BACKGROUND

Interleukin-7 (IL-7) is a non-redundant cytokine for T-cell development and survival. The IL-7 signaling pathway has been genetically and functionally associated with several autoimmune diseases including multiple sclerosis (MS).

OBJECTIVE

The objective of this paper is to elucidate the effect of the widely used immunomodulatory MS therapy interferon beta (IFNβ) on IL-7 homeostasis.

METHODS

Swedish MS patients were screened for IL-7 concentration in serum and blood cell counts. IL-7 receptor alpha chain (IL-7Rα) expression was determined by semi-quantitative real-time polymerase chain reaction (PCR) and flow cytometry.

RESULTS

IFNβ treatment led to significantly increased serum IL-7 levels (mean: 17 pg/ml) compared with healthy controls (mean: 7.6 pg/ml) and natalizumab-treated patients (mean: 5.3 pg/ml). In vitro and in vivo, peripheral blood leukocytes showed decreased IL-7Rα expression and IL-7 consumption upon IFNβ exposure, suggesting that their IL-7 responsiveness is impaired during treatment.

CONCLUSIONS

MS patients undergoing IFNβ treatment have increased serum IL-7 levels and decreased IL-7 consumption. Given IL-7's important role in T-cell immunity, this relationship may be highly relevant for IFNβ's treatment efficacy.

The effect of scheduled antibody testing on treatment patterns in interferon-treated patients with multiple sclerosis

Background

Many patients with relapsing-remitting multiple sclerosis (MS) treated with high-dose interferon-β (IFNβ) develop serum binding antibodies (BAb) and neutralizing antibodies (NAb). NAb reduces the biological activity of IFNβ, which contributes to clinical failure in these patients. We investigated whether access to antibody (Ab) test results would alter usual care of (IFNβ)-treated patients and whether BAb could predict NAb.

Methods

This was a randomized, controlled, open-label, parallel-group, multicenter study in patients with multiple sclerosis. Subjects (n = 1358) were randomly assigned to Ab testing or usual care. BAb and NAb titres were measured using standard assays. Primary and secondary outcomes were the proportion of patients whose IFNβ therapy changed and the type of and reasons for therapy changes.

Results

Therapy changes differed between the Ab testing and usual care arms (19.6% and 14.0%, respectively; p = 0 · 004). Results from Ab testing were more frequently reported as the reason for therapy change in the Ab testing arm than in the usual care arm (p < 0.0001). NAb and BAb positivity significantly increased the likelihood of therapy change and reduced IFNβ-associated adverse events. BAb titres were a significant predictor of NAb positivity (p = 0.0012). Initial BAb-positive and NAb-positive status in both study arms had a significant impact on the overall number of patients with a therapy change (p < 0.05).

Conclusion

Access to Ab test results impacted therapy management. BAb titres can predict NAb positivity in patients on high-dose IFNβ.

Anti-interferon beta antibody titers strongly correlate between two bioassays and in vivo biomarker expression, and indicates that a titer of 150 TRU/mL is a biologically functional cut-point

Interferon beta (IFNβ) is used as a first-line treatment in relapsing-remitting multiple sclerosis (MS). The occurrence of neutralizing antidrug antibodies (NAbs) against IFNβ may reduce treatment response. Therefore, clinical monitoring of NAbs is currently executed using bioassays, but several bioassays are available and it is unclear how well their readouts correlate. We made a comparison between 2 bioassays; myxovirus resistance protein A (MxA) gene expression assay (MGA) and iLite™ anti-Human IFNβ bioassay, to measure IFNβ-specific NAb titers in 44 MS patients. We further studied how NAb titers affected in vivo transcription of IFN-induced genes myxovirus resistant 1 (MX1) and C-X-C motif chemokine 10 (CXCL10), in addition to serum CXCL10 protein levels. There were significant correlations between NAb titer levels measured with MGA and iLite (Spearman r=0.9368). MX1 and CXCL10 gene expression was strongly induced by IFNβ and NAb positivity significantly reduced this expression. A NAb titer of 150 TRU/mL was observed to be a biological cut-point applicable to both assays, since MX1 and CXCL10 expression was greatly reduced or blocked in patients above this titer level. In conclusion, NAb titers measured with the MGA and iLite bioassays are comparable, but the threshold for positivity in both assays does not correspond to the biologically functional cut-point.

Biomarkers of treatment response in multiple sclerosis

Multiple sclerosis (MS) is considered a heterogeneous disease with respect to disease progression and treatment response, which have both remained highly unpredictable. With an increasing number of available disease modifying therapies, strategies for treatment allocation in the individual patient or subgroup of patients has become more important. Therefore biomarkers, which will identify subgroups of MS patients and predict treatment response early in the course of the disease, are urgently needed. Here we review current and emerging biomarkers, as well as study concepts for identification of new biomarkers in MS.

Antibodies to interferon beta in patients with multiple sclerosis receiving CinnoVex, rebif, and betaferon

Treatment with interferon beta (IFN-β) induces the production of binding antibodies (BAbs) and neutralizing antibodies (NAbs) in patients with multiple sclerosis (MS). NAbs against IFN-β are associated with a loss of IFN-β bioactivity and decreased clinical efficacy of the drug. The objective of this study was to evaluate the incidence and the prevalence of binding antibodies (BAbs) and neutralizing antibodies (NAbs) to IFN-β in MS patients receiving CinnoVex, Rebif, or Betaferon. The presence of BAbs was studied in serum samples from 124 MS patients using one of these IFN-β medications by ELISA. The NAbs against IFN-β were measured in BAb-positive MS patients receiving IFN-β using an MxA gene expression assay (real-time RT-PCR). Of the 124 patients, 36 (29.03%) had BAbs after at least 12 months of IFN-β treatment. The proportion of BAb+ was 38.1% for Betaferon, 21.9% for Rebif, and 26.8% for CinnoVex. Five BAb-positive MS patients were lost to follow-up; thus 31 BAb-positive MS patients were studied for NAbs. NAbs were present in 25 (80.6%) of BAb-positive MS patients receiving IFN-β. In conclusion, the three IFN-β preparations have different degrees of immunogenicity.

Efficacy and safety of beta-interferon in Thai patients with demyelinating diseases

BACKGROUND

The efficacy of beta-interferon (IFN-β) treatment in Thai patients with demyelinating diseases has not been reported.

OBJECTIVES

To evaluate the efficacy and any adverse drug reactions of IFN-β therapy in Thai patients, for each group of demyelinating diseases.

METHODS

We retrospectively reviewed data of Thai patients with multiple sclerosis (MS), neuromyelitis optica (NMO) and NMO spectrum disorders (NMOSDs) who attended the MS Clinic at Siriraj Hospital, Thailand from March 2000 to October 2011. We reviewed those 73 patients who received IFN-β. We evaluated the drug's efficacy over 2 years and any adverse drug reactions among these patients.

RESULTS

Of the 40 MS patients who received IFN-β, 26 adhered to the medication for at least 2 years. In addition, 27 NMO/NMOSDs patients who had been diagnosed with MS were treated as such with IFN-β. In the true MS group, the pre- and post-treatment annualized relapse rates (ARR) were 1.25 and 0.59, respectively, so there was a reduction of 52.8% (p = 0.004). In addition, in 69.2% of the patients, IFN-β also showed beneficial effects by prolonging the time to first relapse to 15.9 months and stabilizing or decreasing progression of the disease. In contrast, no significant benefit was seen in the NMO/NMOSDs group. On the contrary, an increase in EDSS was seen in 53.3 % of them. The most common side effects seen were local skin reactions and flu-like symptoms.

CONCLUSIONS

Treatment with IFN-β was effective in reducing both ARR and disability progression in Thai patients with MS. In contrast, we observed that giving IFN-β treatment to NMO/NMOSDs patients may lead to a worsening of symptoms.

Immunogenic effects of recombinant interferon-beta therapy disrupt the JAK/STAT pathway in primary immune cells from patients with multiple sclerosis

BACKGROUND

Immunogenicity of recombinant interferon-β (IFN-β) is a known complication in the therapy of relapsing-remitting multiple sclerosis (RRMS). Neutralizing antibodies (NAbs) that can interfere with efficacy are quantified using in vitro bioassays; however, these assays do not reveal the immunogenic state of the patient and are not predictive of treatment outcome.

OBJECTIVE

Assessment of the impact of NAbs on IFN-β responsive cells and signalling pathways in peripheral blood mononuclear cells (PBMCs) with phospho-specific flow cytometry.

METHOD

PBMCs from 10 IFN-β-treated patients with RRMS, two untreated patients, and two healthy controls were re-stimulated in autologous sera and media with a serial dilution of IFN-β (0-8000 U/ml) and levels of phosphorylation of STAT1/3/4/5/6 transcription factors were quantified in PBMC subtypes (NAb titres 0 to > 6000 neutralizing units). Data was subjected to principal component analysis, Hotelling's T (2), and partial least squares analysis.

RESULTS

Three significantly distinct clusters of individuals were revealed in autologous sera: therapy-naïve and healthy, treated NAb-negative, and treated NAb-positive. Compared with controls STATs signalling patterns were modulated in treated NAb-negative patients and inhibited in all treated NAb-positive patients independently of NAb titres. In media no clustering of patients could be found. The predictability of NAb titres based on the phospho-flow data was 74%.

CONCLUSION

Phospho-specific flow cytometry can delineate subset-specific cell responses that can act as surrogates for NAb exposure in blood. Immunogenic effects alter the response in primary cells even at low NAb levels. Cell line-based immunogenicity testing is not readily transferable to the immunogenic response in patients.

CD49d expression as a promising biomarker to monitor natalizumab efficacy

Natalizumab (Tysabri™), a monoclonal antibody against the α4-integrin of VLA-4 (CD49d) antigen of leukocytes, is highly effective in multiple sclerosis (MS). The most common reason for treatment failure is the development of neutralizing antibodies (NAbs). According to health authorities Nabs testing is recommended in case of relapse or repeated infusion reactions. However NAbs may develop in clinically asymptomatic patients. In this study we investigated if CD49d expression could serve as a biomarker of natalizumab bioavailability and treatment response. In a cohort of 49 natalizumab treated relapsing-remitting MS, followed over 2 years, CD49d expression was determined on peripheral blood mononuclear cells (PBMCs) before each infusion and compared to NAbs and serum natalizumab levels. In a majority of patients (41/49) the CD49d expression in PBMCs was strongly inhibited (>50%) after the first infusion and maintained at low levels throughout the treatment period. In contrast, in eight patients (16%) there was an early recovery of CD49d expression to pre-treatment levels related to NABs development. While three cases experienced hypersensitivity reactions, three others were identified solely on the basis of an undiminished level of CD49d, with neither infusion reaction nor clinical worsening. These 3 patients had very high levels of NAbs and no detectable serum natalizumab. Two additional patients had early but transient recovery of CD49d expression. These patients had low levels of transient Nabs and returned to significant CD49d inhibition after few natalizumab infusions. We suggest that monitoring of CD49d expression can be used as a surrogate biomarker of natalizumab efficiency. If the CD49d expression is sustained at pre-treatment levels, patients should be tested for persistent NAbs and considered for treatment interruption.

Safety profile and practical considerations of monoclonal antibody treatment

INTRODUCTION

Monoclonal antibodies are immunoglobulins specially designed to act against specific targets, in such a way that their administration stops a specific pathogenic process, stimulates a particular cellular action, or changes a cell mechanism to another pathway of interest. Their production is based on the establishment of modified immortal B lymphocytes to produce a specific immunoglobulin. Depending on the level of purity, this immunoglobulin may be murine complement (ending in "o", for example muromonab); chimeric, in which all the immunoglobulin is human, except in the variable region which is murine (ending in "xi", for example, rituximab); humanised, in which all the immunoglobulin is human, except in the variable complement region which remains murine (ending in "zu", for example, natalizumab); and human complement (ending in "u", for example, adalimumab). Therefore, there will be two types of secondary effects: those arising from the action of the antibody, such as opportunistic infections due to immunosuppression, and those arising from the administration of a protein, such as anaphylactic reactions. The sources used for the present articles were articles published in PubMed, located by searching for "Monoclonal antibodies and Secondary effects", and the web pages of the European Medicines Agency (EMEA) and the US Food and Drus Administration (FDA).

DEVELOPMENT

The secondary effects arising from the mechanisms of action were opportunistic infections, common infections, development of tumours and autoimmune phenomena, and those arising from the administration of proteins: anaphylactic reaction, cytokine release syndrome, and the development of neutralising antibodies. Finally, the management of monoclonal antibodies in clinical practice and in special situations is discussed, including administering vaccines, pregnancy and paediatric use. Reference will be made to immune recovery syndrome.

CONCLUSIONS

Monoclonal antibodies are highly effective drugs when specifically indicated, but they also may incur serious secondary effects, which although incidence is low, require close monitoring of the patients receiving these treatments.

Frequency and magnitude of interferon β neutralizing antibodies in the evaluation of interferon β immunogenicity in patients with multiple sclerosis

Patients with multiple sclerosis (MS) treated with interferon β (IFNβ) preparations develop varying levels of antibodies that neutralize the biological effects of IFNβ, reduce its in vivo bioavailability, and diminish its therapeutic efficacy. The aim was to determine as distinct measures of immunogenicity the occurrence (frequency) and the magnitude (level) of IFNβ neutralizing antibody (NAb) formation in a large Canadian population as a cross-sectional study of patients with MS treated in a clinical practice setting with different, equally available IFNβ products: Avonex(®) (intramuscular IFNβ-1a), Rebif(®) (subcutaneous (SC) IFNβ-1a) at 22 and 44 μg, and Betaseron(®) (SC IFNβ-1b). Over a 3-year period 3,124 serum samples from 2,711 patients with MS were submitted by neurologists in MS clinics distributed across Canada and tested for NAbs in a single independent laboratory, utilizing a quantitative, standardized NAb bioassay. NAb frequency was greatest (35%) with Rebif (SC IFNβ-1a) 44 μg and least (7.5%) with Avonex (intramuscular IFNβ-1a), whereas Betaseron (IFNβ-1b) and Rebif 22 μg were in between (22%). NAb serum levels at magnitudes considered high, ≥100 tenfold reduction units (TRU)/mL, were found in 65%-83% of patients with detectable NAbs. Nearly half (42%-47%) of NAb-positive patients given IFNβ-1a preparations had very high titers (≥ 1,000 TRU/mL), whereas only 22% of NAb-positive patients on Betaseron had titers >1,000 TRU/mL. Differences in patterns of NAb formation among the four IFNβ product-dose combinations became more evident in patients with MS when both NAb frequency and the full range of NAb titer magnitude were measured.

Impact of product-related factors on immunogenicity of biotherapeutics

All protein therapeutics have the potential to be immunogenic. Several factors, including patient characteristics, disease state, and the therapy itself, influence the generation of an immune response. Product-related factors such as the molecule design, the expression system, post-translational modifications, impurities, contaminants, formulation and excipients, container, closure, as well as degradation products are all implicated. However, a critical examination of the available data shows that clear unequivocal evidence for the impact of these latter factors on clinical immunogenicity is lacking. No report could be found that clearly deconvolutes the clinical impact of the product attributes on patient susceptibility. Aggregation carries the greatest concern as a risk factor for immunogenicity, but the impact of aggregates is likely to depend on their structure as well as on the functionality (e.g., immunostimulatory or immunomodulatory) of the therapeutic. Preclinical studies are not yet capable of assessing the clinically relevant immunogenicity potential of these product-related factors. Simply addressing these risk factors as part of product development will not eliminate immunogenicity. Minimization of immunogenicity has to begin at the molecule design stage by reducing or eliminating antigenic epitopes and building in favorable physical and chemical properties.

Safety, Tolerability, and Immunogenicity of Interferons

Interferons (IFNs) are class II cytokines that are key components of the innate immune response to virus infection. Three IFN sub-families, type I, II, and III IFNs have been identified in man, Recombinant analogues of type I IFNs, in particular IFNα2 and IFNβ1, have found wide application for the treatment of chronic viral hepatitis and remitting relapsing multiple sclerosis respectively. Type II IFN, or IFN gamma, is used principally for the treatment of chronic granulomatous disease, while the recently discovered type III IFNs, also known as IFN lambda or IL-28/29, are currently being evaluated for the treatment of chronic viral hepatitis. IFNs are in general well tolerated and the most common adverse events observed with IFNα or IFNβ therapy are “flu-like” symptoms such as fever, headache, chills, and myalgia. Prolonged treatment is associated with more serious adverse events including leucopenia, thrombocytopenia, increased hepatic transaminases, and neuropsychiatric effects. Type I IFNs bind to high-affinity cell surface receptors, composed of two transmembrane polypeptides IFNAR1 and IFNAR2, resulting in activation of the Janus kinases Jak1 and Tyk2, phosphorylation and activation of the latent cytoplasmic signal transducers and activators of transcription (STAT1) and STAT2, formation of a transcription complex together with IRF9, and activation of a specific set of genes that encode the effector molecules responsible for mediating the biological activities of type I IFNs. Systemic administration of type I IFN results in activation of IFN receptors present on essentially all types of nucleated cells, including neurons and hematopoietic stem cells, in addition to target cells. This may well explain the wide spectrum of IFN associated toxicities. Recent reports suggest that certain polymorphisms in type I IFN signaling molecules are associated with IFN-induced neutropenia and thrombocytopenia in patients with chronic hepatitis C. IFNγ binds to a cell-surface receptor composed of two transmembrane polypeptides IFGR1 and IFGR2 resulting in activation of the Janus kinases Jak1 and Jak2, phosphorylation of STAT1, formation of STAT1 homodimers, and activation of a specific set of genes that encode the effector molecules responsible for mediating its biological activity. In common with type I IFNs, IFNγ receptors are ubiquitous and a number of the genes activated by IFNγ are also activated by type I IFNs that may well account for a spectrum of toxicities similar to that associated with type I IFNs including “flu-like” symptoms, neutropenia, thrombocytopenia, and increased hepatic transaminases. Although type III IFNs share the major components of the signal transduction pathway and activate a similar set of IFN-stimulated genes (ISGs) as type I IFNs, distribution of the IFNλ receptor is restricted to certain cell types suggesting that IFNλ therapy may be associated with a reduced spectrum of toxicities relative to type I or type II IFNs. Repeated administration of recombinant IFNs can cause in a break in immune tolerance to self-antigens in some patients resulting in the production of neutralizing antibodies (NABs) to the recombinant protein homologue. Appearance of NABs is associated with reduced pharmacokinetics, pharmacodynamics, and a reduced clinical response. The lack of cross-neutralization of IFNβ by anti-IFNα NABs and vice versa, undoubtedly accounts for the apparent lack of toxicity associated with the presence of anti-IFN NABs with the exception of relatively mild infusion/injection reactions.

The safety and side effects of monoclonal antibodies

Monoclonal antibodies (mAbs) are now established as targeted therapies for malignancies, transplant rejection, autoimmune and infectious diseases, as well as a range of new indications. However, administration of mAbs carries the risk of immune reactions such as acute anaphylaxis, serum sickness and the generation of antibodies. In addition, there are numerous adverse effects of mAbs that are related to their specific targets, including infections and cancer, autoimmune disease, and organ-specific adverse events such as cardiotoxicity. In March 2006, a life-threatening cytokine release syndrome occurred during a first-in-human study with TGN1412 (a CD28-specific superagonist mAb), resulting in a range of recommendations to improve the safety of initial human clinical studies with mAbs. Here, we review some of the adverse effects encountered with mAb therapies, and discuss advances in preclinical testing and antibody technology aimed at minimizing the risk of these events.

Influence of interferon-beta therapy switching on neutralizing antibody titres: results from the Austrian Switch Study

Neutralizing antibodies against interferon-beta are associated with a reduction of the efficacy of this drug. Continuing treatment leads to a decline or even loss of neutralizing antibodies over years. No strategies are currently available to shorten the period of neutralizing antibody positivity. The objective of this study was to investigate the effect of switching between high and low immunogenic interferon-beta products on neutralising antibody titres. Twenty-four patients treated with the subcutaneously administered interferon-beta 1b or 1a and high titres of neutralizing antibodies were included. At baseline interferon-beta therapy was interrupted for 3 months and two pulses of high dose methylprednisolone were applied. Patients were then randomized to receive either the previous interferon-beta preparation or the low immunogenic intramuscular interferon-beta 1a. The primary end-point was the change of neutralizing antibody titres 12 months after randomization. Twelve patients were switched to interferon-beta 1a intramuscularly and 12 patients remained on previous treatment. Median neutralizing antibody titres were 846 NU at baseline and 196 NU at the end of the study. The median change of neutralizing antibody titres did not differ significantly between therapy switchers and non-switchers. Baseline and final neutralizing antibody titres correlated significantly. In conclusion, neither switching nor continuous therapy with any subcutaneous interferon-beta preparation significantly changed neutralizing antibody titres.

Hybrid transgenic immune tolerant mouse model for assessing the breaking of B cell tolerance by human interferon beta

To date, the therapeutic efficacy of recombinant human proteins is limited by their potential to break B cell tolerance in patients. The formation of neutralising antibodies (NABs) directed against recombinant human interferon beta (rhIFNbeta) is associated with a decrease in the therapeutic effect of the protein. For this reason, there is a need to study factors that can cause the immunogenicity of rhIFNbeta. Transgenic C57Bl/6 mice that are immune tolerant for human interferon beta (hIFNbeta) have been employed in a mouse model for assessing the breaking of immune tolerance by rhIFNbeta. In this study, we used the original C57Bl/6 mouse model as well as the hybrid offspring from crossings of transgenic C57Bl/6 mice with wildtype FVB/N mice to study the immunogenicity of three commercial rhIFNbeta products, Rebif, Avonex and Betaferon. As determined by ELISA, wildtype C57Bl/6 mice failed to form binding antibodies (BABs) against Rebif and Avonex formulated with human serum albumin. Because not all interferon beta products induce antibodies in wildtype C57Bl/6 mice, the transgenic C57Bl/6 mice cannot be used to study the breaking of tolerance by these products. However, the crossing of transgenic C57Bl/6 mice with FVB/N mice resulted in wildtype hybrid offspring in which all products were immunogenic and transgenic hybrid offspring that showed immune tolerance for hIFNbeta. Thus, these C57Bl/6 x FVB/N hybrid transgenic mice can be used to study the breaking of immune tolerance for all rhIFNbeta products. Of the three products, only Betaferon was able to break immune tolerance in the transgenic hybrids. With an MxA gene expression inhibition assay, NABs were detected in Betaferon treated wildtype hybrid mice, but not in transgenic hybrid mice, indicating a distinct immune mechanism in wildtype and transgenic mice. A pegylated rhIFNbeta-1a variant, PEG-rhIFNbeta-1a, induced antibodies in wildtype hybrid mice, but did not break the immune tolerance of transgenic hybrid mice. This suggests that pegylation did not affect the potential of rhIFNbeta-1a to break B cell tolerance.